Place a large pot or high-sided skillet filled with water over high heat to boil. Season the boiling water with salt and drop the beans in. Cook until bright green and tender, about 3 minutes. Drain the beans and return them to the pan. Return to medium heat and add in the olives and butter. Season with some salt and pepper and toss to melt the butter and coat the beans. Serve alongside Spanish-Style Chicken with Crispy Chorizo and Chimichurri.